Using Test Positivity Rate (TPR) as an Indicator for Strategic Action in COVID-19: A Situational Analysis in Kerala, India

Administrators and policymakers have relied on test positivity rate (TPR) for making policy decisions regarding local, regional, and national lockdowns. It has the advantage of easily available data with an easy technique for calculation on day-to-day basis. However, concerns are being raised regarding its use as a sole indicator for determining movement restrictions and lockdowns. The present review provides a perspective of the alterations in TPR in Kasaragod district of Kerala during the first half of 2021. The variations in the number of antigen and reverse transcription polymerase chain reaction (rt-PCR) tests along with the trend of proportion of rt-PCR test are depicted. In places like Kerala where primary care system and contact tracing is comparatively robust than several other regions, testing the appropriate persons in a timely fashion alone is sufficient to cause an upswing in the TPR. Rather than daily change, the overall change in a larger time frame of 1 to 2 weeks could give early warning regarding the emergence of a new wave. TPR alone may not be able to reflect the transmission patterns of COVID-19. Using 7-day median value of TPR along with weekly tests done per 10,000 population, 7-day rolling average of active cases per 10,000 population, or daily number of new positive cases per 10,000 population could bring out a more composite indicator. Such an indicator reflecting the disease dynamics at regional levels will enable people to improve their livelihood without compromising on COVID-19.

Freeze-thaw Assessment of Plants Based on Envelope Analysis of Stem Volume Water Content Sequence

Background: Frost stress is an abiotic stressor for plant growth that impacts the health and the regional distribution of plants. The freeze-thaw characteristics of plants during the overwintering period help to understand relevant issues in plant physiology, including plant cold resistance and cold acclimation. Therefore, we aimed to develop a non-invasive instrument and method for accurate in situ detection of changes in stem freeze-thaw characteristics during the overwintering period. Results: A sensor was designed based on standing wave ratio method (SWR) to measure stem volume water content (StVWC). We were able to measure stem volume ice content (StVIC) and stem freeze-thaw rate of ice (StFTRI) during the overwintering period. The resolution of the StVWC sensor is less than 0.05 %, the mean absolute error and root mean square error are less than 1 %, and the dynamic response time is 0.296 s. The peak point of the daily change rate of the lower envelope of the StVWC sequence occurs when the plant enters and exits the overwintering period. The peak point can be used to determine the moment of freeze-thaw occurrence, whereas the time point corresponding to the moment of freeze-thaw coincides with the rapid transition between high and low ambient temperatures. In the field, the StVIC and StFTRI of Juniperus virginiana L., Lagerstroemia indica L. and Populus alba L. gradually increased at the beginning, fluctuated steadily during, and then gradually decreased by the end of the overwintering period. The StVIC and StFTRI also showed significant variability due to differences among the tree species and latitude.Conclusions: The StVWC sensor has good resolution, accuracy, stability, and sensitivity. The envelope changes of the StVWC sequence and the correspondence between the freeze-thaw moment and the ambient temperature indicate that the determination of the freeze-thaw moment based on the peak point of the daily change rate of the lower envelope is reliable. The results show that the sensor is able to monitor changes in the freeze-thaw characteristics of plants and effectively characterize freeze-thaw differences and cold resistance of different tree species. Furthermore, this is a cost-effective tool for monitoring freeze-thaw conditions during the overwintering period.

The Circadian Clock Gene Bmal1 Modulates Myometrium Contractile Function in Pregnant Mice

Caesarian section should be avoided unless medically required. Caesarian section is often a result of failed labor enhancement. While most natural births occur at night, labor enhancement is often scheduled during the day. We propose that the disparity between the commonly used timing of labor enhancement in the clinic, from the timing of natural birth, could contribute to the high rate of labor induction failure. Oxytocin receptor agonists are the most used labor enhancing agents. In pregnant non-human primates, oxytocin enhances uterine contractions more efficiently at night than during the day, suggesting a daily change in uterine sensitivity to oxytocin in pregnancy. To identify the molecular mechanisms generating daily changes in uterine function, we here explore the role of the molecular clock gene, Bmal1 (Brain and muscle ARNTL1-like), in the pregnant mouse myometrium. BMAL1 is a transcription factor required to generated circadian rhythms at the cellular level. We hypothesize that Bmal1 in uterine myometrial cells generates circadian rhythms and establishes the daily change in uterine contractile response to oxytocin. To evaluate circadian rhythms ex vivo, we collected myometrium samples from the validated circadian Per2:luciferase reporter mice at gestation day 17-18. We found that the pregnant mouse myometrium possesses circadian rhythms, which are generated by the molecular clock, as triple transgenic Per2:luciferase mice with Bmal1 conditionally deleted in the myometrium (cKO) do not have rhythmic expression of the Per2:luciferase reporter. To determine if BMAL1 is required to establish uterine contractions, we used a myograph to measure ex vivo uterine contractions at gestation day 17-18. In controls, uterine contraction force was significantly higher at ZT15 (3h after lights OFF) versus ZT3 (3h after lights ON). Interestingly, our preliminary data show increased basal contractile force at ZT15 in cKO as compared to controls. In addition, the cKO uterus contracted stronger to oxytocin than controls. Our findings identify Bmal1 as a clock gene modulating basal contractions in the mouse uterus and indicate Bmal1 might be a regulator of uterine sensitivity to oxytocin. Future work will focus on identifying the molecular mechanisms driven by BMAL1 to regulate uterine function in pregnancy. This work has the potential to provide insights into how we can improve labor enhancing treatment strategies in the clinic in the future.

Determining the influence of snow and temperature on the movement rates of wood bison (Bison bison athabascae)

Snow is understood to limit wildlife movements, often being the most important determinant of winter movement for animals in the boreal forest. However, the combined effect of snow and temperature on the movement ecology of animals at high latitudes is less understood. We used GPS-collar data from a small population of wood bison (Bison bison athabascae Rhoads, 1898) in northeastern Alberta, Canada to develop a series of generalized additive mixed models characterizing the effect of cumulative snow depth, daily change in snow depth, and temperature on movement rates. Our most supported model included cumulative snow depth, temperature, and day of winter. Bison movements decreased in the first 75 days of winter during snow accumulation, and dramatically increased in the final 14 days of winter during snow melt. Cumulative snow depth, not daily change in snow depth, reduced wood bison movement rates, and movement rates increased more rapidly in warmer temperatures than in temperatures below -6.4 °C. By quantifying both the direction and magnitude of snow and temperature’s effects on bison movement, our study fills critical knowledge gaps relating to the winter movement ecology of wood bison and contributes to a growing body of knowledge informing their conservation in the Anthropocene.

Reduced mortality in COVID-19 patients treated with colchicine: Results from a retrospective, observational study

Objectives Effective treatments for coronavirus disease 2019 (COVID-19) are urgently needed. We hypothesized that colchicine, by counteracting proinflammatory pathways implicated in the uncontrolled inflammatory response of COVID-19 patients, reduces pulmonary complications, and improves survival. Methods This retrospective study included 71 consecutive COVID-19 patients (hospitalized with pneumonia on CT scan or outpatients) who received colchicine and compared with 70 control patients who did not receive colchicine in two serial time periods at the same institution. We used inverse probability of treatment propensity-score weighting to examine differences in mortality, clinical improvement (using a 7-point ordinary scale), and inflammatory markers between the two groups. Results Amongst the 141 COVID-19 patients (118 [83.7%] hospitalized), 70 (50%) received colchicine. The 21-day crude cumulative mortality was 7.5% in the colchicine group and 28.5% in the control group (P = 0.006; adjusted hazard ratio: 0.24 [95%CI: 0.09 to 0.67]); 21-day clinical improvement occurred in 40.0% of the patients on colchicine and in 26.6% of control patients (adjusted relative improvement rate: 1.80 [95%CI: 1.00 to 3.22]). The strong association between the use of colchicine and reduced mortality was further supported by the diverging linear trends of percent daily change in lymphocyte count (P = 0.018), neutrophil-to-lymphocyte ratio (P = 0.003), and in C-reactive protein levels (P = 0.009). Colchicine was stopped because of transient side effects (diarrhea or skin rashes) in 7% of patients. Conclusion In this retrospective cohort study colchicine was associated with reduced mortality and accelerated recovery in COVID-19 patients. This support the rationale for current larger randomized controlled trials testing the safety/efficacy profile of colchicine in COVID-19 patients.

An exploratory study on the correlation of population SARS-CoV-2 cycle threshold values to local disease dynamics

ABSTRACTIntroductionDespite limitations on the use of cycle threshold (CT) values for individual patient care, population distributions of CT values may be useful indicators of local outbreaks.MethodsSpecimens from the greater El Paso area were processed in the Dascena COVID-19 Laboratory. Daily median CT value, daily transmission rate R(t), daily count of COVID-19 hospitalizations, daily change in percent positivity, and rolling averages of these features were plotted over time. Two-way scatterplots and linear regression evaluated possible associations between daily median CT and outbreak measures. Cross-correlation plots determined whether a time delay existed between changes in the daily median CT value and measure of community disease dynamics.ResultsDaily median CT was negatively correlated with the daily R(t), the daily COVID-19 hospitalization count (with a time delay), and the daily change in percent positivity among testing samples. Despite visual trends suggesting time delays in the plots for median CT and outbreak measures, a statistically significant delay was only detected between changes in median CT and COVID-19 hospitalization count.ConclusionsThis study adds to the literature by analyzing samples collected from an entire geographical area, and contextualizing the results with other research investigating population CT values.

Estimation of the efficiency of cowshed aeration in the warm season

Heat stress is one of the main factors affecting the well-being and performance of cows during the warm season. The article presents the results of calculating the daily change in the ventilation air consumption during the cowshed aeration. The influence of changes in the outside air temperature on the amount of air exchange was revealed.

Crop-photoperiodism model 2.0 for the panicle-initiation date of sorghum and rice that includes daily changes in sunrise and sunset times

Background and Aims: Daylength determines flowering dates. However, questions remain regarding flowering dates in the natural environment, such as the synchronous flowering of plants sown simultaneously at highly contrasting latitudes. The daily change in sunrise and sunset times is the cue for the flowering of trees and for the synchronisation moulting in birds at the equator. Sunrise and sunset also synchronise the cell circadian clock, which is involved in the regulation of flowering. The goal of this study was to update the photoperiodism model with knowledge acquired since its conception. Methods: A large dataset was gathered, including four 2-year series of monthly sowings of 28 sorghum varieties in Mali and two 1-year series of monthly sowings of eight rice varieties in the Philippines to compare with previously published monthly sowings in Japan and Malaysia, and data from sorghum breeders in France, Nicaragua, and Colombia. An additive linear model of the duration in days to panicle initiation (PI) using day length and daily changes in sunrise and sunset times was implemented. Key Results: Simultaneous with the phyllochron, the duration to PI of field crops acclimated to the mean temperature at seedling emergence within the usual range of mean cropping temperatures. A unique additive linear model combining daylength and daily changes in sunrise and sunset hours was accurately fitted for any type of response in the duration to PI to the sowing date without any temperature input. Once calibrated on a complete and an incomplete monthly sowing series at two tropical latitudes, the model accurately predicted the duration to PI of the concerned varieties from the equatorial to the temperate zone. Conclusions: The results of the updated photoperiodism model strongly supported the hypothesis that photoperiodism could be a combined response to day length and daily changes in sunrise and sunset times.